1. Field of the Invention
The present invention relates to a ceiling transport vehicle comprising a travel portion that travels along a guide rail installed on a ceiling side along a set travel path, a main body portion that is suspended and supported by the travel portion and that supports an article such that the article can be moved vertically, and a pair of guiding bodies that contact right and left lateral sides of the guide rail to guide the travel portion along the set travel path.
2. Description of Related Art
Such ceiling transport vehicles are configured to guide its travel portion, which travels on a guide rail along a set travel path, with a pair of guiding bodies, and to vertically move an article with the travel portion stopped at an article transfer position, which is arranged at a location that corresponds to an article transfer target location in the travel path, so as to transfer the article to and from the article transfer target location.
And in such a conventional ceiling transport vehicle, the pair of guiding bodies are caused to contact right and left lateral side faces of the guide rail to restrict the movement of the travel portion relative to the guide rail in the lateral width direction, thereby to restrict a displacement of the travel portion in the lateral width direction with respect to the article transfer position when the travel portion is stopped. The ceiling transport vehicle is configured to transfer an article to and from an article transfer target location with the displacement of the travel portion in the lateral width direction being restricted with respect to the article transfer position in this manner. (See, for example, Patent Document 1.)
In this conventional ceiling transport vehicle, the guide rail consists of a pair of rail portions spaced apart from each other in the lateral width direction. And the pair of guiding bodies are provided between the pair of rail portions such that the pair of guiding bodies contact respective inward faces of the rail portions (i.e., a left hand side surface of the right hand side rail portion, and the right hand side surface of the left hand side rail portion) which face each other and which define the right and left lateral side faces of the guide rail. And even if there are locations where the distance between the pair of rail portions is narrower due to inaccuracies in the installation of the pair of rail portions or changes that occur over time, the pair of guiding bodies are configured or positioned such that the pair of guiding bodies will not be caught and stuck at these locations, so that the travel portion can travel smoothly along a set travel path. More specifically, for example, by forming the pair of guiding bodies with resilient members so that they can deform elastically, or by positioning the pair of guiding bodies such that they can retreat away from the rail portions and urging them toward the rail portions, the pair of guiding bodies are configured or positioned such that they will not be caught and get stuck at a location where the distance between the pair of rail portions is narrower so that the travel portion can travel smoothly along the set travel path.